Plasma processing apparatuses are used to process semiconductor substrates by techniques including etching, physical vapor deposition (PVD), chemical vapor deposition (CVD), and resist removal. One type of plasma processing apparatus used in plasma processing includes a reaction chamber containing top and bottom electrodes. A radio frequency (RF) power is applied between the electrodes to excite a process gas into a plasma for processing semiconductor substrates in the reaction chamber.
One challenge facing designers of plasma processing chambers is that the plasma etch conditions create significant ion bombardment of the surfaces of the processing chamber that are exposed to the plasma. This ion bombardment, combined with plasma chemistries and/or etch byproducts, can produce significant erosion, corrosion and corrosion-erosion of the plasma-exposed surfaces of the processing chamber. Another challenge is to control etch rate uniformity across a semiconductor substrate (e.g., silicon substrate), in particular, to make the etch rate at the center of the substrate equal to the etch rate at the edge. To alleviate such nonuniformities, a hot edge ring and an underlying RF coupling ring have been implemented fitting around the substrate. The hot edge ring is a consumable part and requires regular cleaning or replacement. It is desirable to extend the lifetime of the hot edge ring in order to increase mean time between cleaning or replacement and to decrease the cost of ownership. A hot edge ring with extended RF lifetime is described herein.